Are you sure your seal is good? It is easy to have a gap around the bottom/back edge with Empy cups. A little swivelling around easily solves this issue. Also, the bass feels tighter with leather pads versus velour.
At the end of the day perhaps this bass is just not for you? In my experience the LCD4 has slightly better bass than the Empy; cleaner and tighter. But even as a bass addict I am very happy with the Empy's bass being a very close second in this regard. Not to mention that lifelike mid section and opened treble vs. the LCD4.
Utopia is tight and fast, but doesn't have the meaty and substantial bass of Empy. Also, HEKSE has a more spacious bass, but nowhere near as organic and satisfying as Empy bass. At least to my taste. YMMV.